mysql - Reuse Value from SELECT in WHERE -


is possible reuse value select in where clause?
fine if possible other way around: reuse value where in select. want increase readability , performance: guess modern sql server won't calculate value twice.

select `e`.*, (datediff(e.start, 'somevalue')) `offset` `event` `e` `offset` % someinterval = 0

instead

select `e`.*, (datediff(e.start, 'somevalue')) `offset` `event` `e` (datediff(e.start, 'somevalue')) % someinterval = 0

use having instead of where:

select `e`.*, (datediff(e.start, 'somevalue')) `offset` `event` `e` having `offset` % someinterval = 0

where used decide rows put result set, have infinite regress if refer results @ same time selecting them.

having used filter results after they're calculated.


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